Java

实体类

import java.util.Date;

public class User {
    private Integer id;
    private String username;
    private Integer sex;
    private Integer age;
    private Date createDate;
    private Integer isDel;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public Integer getSex() {
        return sex;
    }
    public void setSex(Integer sex) {
        this.sex = sex;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public Date getCreateDate() {
        return createDate;
    }
    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }
    public Integer getIsDel() {
        return isDel;
    }
    public void setIsDel(Integer isDel) {
        this.isDel = isDel;
    }
    @Override
    public String toString() {
        return "User [id=" + id + ", username=" + username + ", sex=" + sex + ", age=" + age + ", createDate="
                + createDate + ", isDel=" + isDel + "]";
    }

}

JDBC工具类 - 获得连接

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DBUtil {
    
    private static final String URL = "jdbc:mysql:///imooc";
    private static final String USER = "root";
    private static final String PASSWORD = "root";
    
    private static Connection conn = null;
    
    static {
        try {
            //1.加载驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            //2.获得数据库的连接
            conn = DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    
    public static Connection getConn(){
        return conn;
    }
    
}

数据持久类

import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.imooc.db.DBUtil;
import com.imooc.model.User;

public class UserDao {

    public void addUser(User u) throws SQLException{
        Connection conn = DBUtil.getConn();
        String sql = "insert into user (user_name,sex,age,create_date,isdel) values(?,?,?,current_date(),?)";
        PreparedStatement ptmt = conn.prepareStatement(sql);
        ptmt.setString(1, u.getUsername());
        ptmt.setInt(2, u.getSex());
        ptmt.setInt(3, u.getAge());
        ptmt.setInt(4, u.getIsDel());
        ptmt.execute();
    }
    
    public void deleteUser(Integer id) throws SQLException{
        Connection conn = DBUtil.getConn();
        String sql = "delete from user where id=?";
        PreparedStatement ptmt = conn.prepareStatement(sql);
        ptmt.setInt(1, id);
        ptmt.execute();
    }
    
    public void updateUser(User u) throws SQLException{
        Connection conn = DBUtil.getConn();
        String sql = "update user set user_name=?,sex=?,age=?,create_date=?,isdel=? where id=?";
        PreparedStatement ptmt = conn.prepareStatement(sql);
        ptmt.setString(1, u.getUsername());
        ptmt.setInt(2, u.getSex());
        ptmt.setInt(3, u.getAge());
        ptmt.setDate(4, new Date(u.getCreateDate().getTime()));
        ptmt.setInt(5, u.getIsDel());
        ptmt.setInt(6, u.getId());
        ptmt.execute();
    }
    
    public List<User> conditionQuery(List<Map<String, Object>> params) throws SQLException{
        Connection conn = DBUtil.getConn();
        StringBuilder sb = new StringBuilder();
        sb.append("select * from user where 1=1 ");
        if(params!=null && params.size()>0){
            for (Map<String, Object> param : params) {
                sb.append("and "+param.get("field")+param.get("rela")+param.get("value"));
            }
        }
        System.out.println(sb.toString());
        PreparedStatement ptmt = conn.prepareStatement(sb.toString());
        ResultSet rs = ptmt.executeQuery();
        
        List<User> users = new ArrayList<>();
        User u = null;
        while(rs.next()){
            u = new User();
            u.setId(rs.getInt("id"));
            u.setUsername(rs.getString("user_name"));
            u.setSex(rs.getInt("sex"));
            u.setAge(rs.getInt("age"));
            u.setCreateDate(rs.getDate("create_date"));
            u.setIsDel(rs.getInt("isdel"));
            users.add(u);
        }
        return users;
    }
    
    public List<User> queryAll() throws SQLException{
        Connection conn = DBUtil.getConn();
        StringBuilder sb = new StringBuilder();
        sb.append("select * from user");
        PreparedStatement ptmt = conn.prepareStatement(sb.toString());
        ResultSet rs = ptmt.executeQuery();
        List<User> users = new ArrayList<>();
        User u = null;
        while(rs.next()){
            u = new User();
            u.setId(rs.getInt("id"));
            u.setUsername(rs.getString("user_name"));
            u.setSex(rs.getInt("sex"));
            u.setAge(rs.getInt("age"));
            u.setCreateDate(rs.getDate("create_date"));
            u.setIsDel(rs.getInt("isdel"));
            users.add(u);
        }
        return users;
    }
    
    public User queryOne(Integer id) throws SQLException{
        Connection conn = DBUtil.getConn();
        StringBuilder sb = new StringBuilder();
        sb.append("select * from user where id=?");
        PreparedStatement ptmt = conn.prepareStatement(sb.toString());
        ptmt.setInt(1, id);
        ResultSet rs = ptmt.executeQuery();
        User u = new User();
        u.setId(rs.getInt("id"));
        u.setUsername(rs.getString("user_name"));
        u.setSex(rs.getInt("sex"));
        u.setAge(rs.getInt("age"));
        u.setCreateDate(rs.getDate("create_date"));
        u.setIsDel(rs.getInt("isdel"));
        return u;
    }
    
}

控制类

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.imooc.dao.UserDao;
import com.imooc.model.User;

public class Action {

    private UserDao dao;
    
    public void add(User u) throws SQLException {
        dao = new UserDao();
        dao.addUser(u);
    }
    
    public void delete(Integer id) throws SQLException{
        dao = new UserDao();
        dao.deleteUser(id);
    }
    
    public void update(User u) throws SQLException{
        dao = new UserDao();
        dao.updateUser(u);
    }
    
    public void conditionQuery() throws SQLException{
        dao = new UserDao();
        List<Map<String, Object>> params = new ArrayList<>();
        Map<String, Object> param = new HashMap<>();
        param.put("field", "user_name");
        param.put("rela", "=");
        param.put("value", "'望望'");
        params.add(param);
        param.put("field", "id");
        param.put("rela", "=");
        param.put("value", "'2'");
        params.add(param);
        
        List<User> users = dao.conditionQuery(params);
        for (User u : users) {
            System.out.println(u);
        }
    }
    
    public List<User> queryAll() throws SQLException{
        dao = new UserDao();
        return dao.queryAll();
    }
    
    public User queryOne(Integer id) throws SQLException{
        dao = new UserDao();
        return dao.queryOne(id);
    }

}